1. Technical Field
The present invention relates to a printer that prints forms and tickets, and a printing system that uses this printer. More particularly, the invention relates to a printer that can calculate and output paper consumption indicating how much paper is consumed in a single printing operation, and to a printing system that uses this printer.
2. Related Art
Printers commonly have a configuration known as a maintenance counter that internally measures and stores maintenance data such as the cumulative amount of paper fed through the printer. The maintenance counter is formed in nonvolatile memory, and typically includes two counters, a cumulative counter that measures the maintenance data continuously from the first use of the printer after shipping from the factory, and a resettable counter that can be reset by a specific command. The count from the cumulative counter enables knowing total usage from when the printer shipped, for example. The resettable counter can be reset each time a consumable material used by the printer is replaced, and by issuing a warning when the count of this counter exceeds a specific value, the user can know that the consumable must be replaced or maintenance is required.
JP-A-H06-312559 teaches a printer with this type of maintenance counter. The disclosed printer has a nonvolatile first maintenance counter that counts the length of the conveyed paper, indicates when parts need replacing, and can be cleared in a specific mode, and a nonvolatile second maintenance counter that counts the conveyed paper length and cannot be cleared.
The count from the first maintenance counter is used to manage the service life of consumable parts such as the platen. When the count reaches a specific value, consumable parts are replaced and the first maintenance counter is cleared in order to manage the service life of the newly installed parts.
The second maintenance counter is not cleared even in the specific mode entered when replacing parts, continues counting the conveyed paper length, and the count from this counter can therefore be used to manage total usage from when the printer shipped.
The maintenance counter used in the disclosed printer cannot be frequently reset because the count is stored in nonvolatile memory, and the maintenance data that is counted is limited to maintenance data that is kept for a relatively long time, such as the interval until consumable parts are replaced. For example, the conveyed paper length used as maintenance data is reset when consumable parts are replaced in the paper feed mechanism or when maintenance is performed on the paper feed mechanism.
As a result, the maintenance counter according to the related art cannot acquire information related to paper consumption by the printer during an extremely short period of time, such as how much paper is consumed in a single printing operation (print job), or more particularly the amount of paper (length of paper) used to print one form or ticket, for example. In addition, the amount of paper consumed or the paper consumption status of the printer during a particular period of time specified by the user cannot be easily obtained.
Furthermore, because the maintenance counter of a conventional printer is for measuring printer maintenance data, the paper feed length that is counted as the maintenance data is the total length of paper conveyed by the paper feed mechanism, that is, the total distance that paper is conveyed by the paper feed mechanism in both the forward and reverse directions. As a result, paper consumption in a single printing operation, or more specifically the forward conveyance distance, cannot be accurately determined from the count of the maintenance counter. For example, the length of paper used by the printer to print a label, receipt, or coupon cannot be accurately confirmed from the count kept by the maintenance counter.